1. Field of the Invention
The present invention relates to a silicone resin, a sealing material, and an optical semiconductor device, in particular, to a silicone resin, a sealing material composed of the silicone resin, and an optical semiconductor device in which the sealing material is used.
2. Description of Related Art
Conventionally, a silicone resin with excellent transparency has been used as a sealing material for an optical semiconductor element such as a light emitting diode (LED). Such a silicone resin is in a liquid state at room temperature, and the silicone resin is applied to the optical semiconductor element and cured by heating, thereby sealing in an optical semiconductor element.
Furthermore, in view of storage stability and handleability, a silicone resin that is in solid state at room temperature is also used. As such a solid silicone resin, for example, Japanese Unexamined Patent Publication No. 2000-154252 has proposed a silsesquioxane-containing polymer obtained by allowing pentacyclo[9.5.1.13.9.15.15.17.13]octasiloxane to react with 1,3-divinyltetramethyldisiloxane.
Also, Japanese Unexamined Patent Publication No. 2002-69191 has proposed a polysiloxane obtained by allowing hydrogenated octasilsesquioxane to react with disilanol.
The sealing materials proposed in Japanese Unexamined Patent Publication No. 2000-154252 and Japanese Unexamined Patent Publication No. 2002-69191 are plasticized by heating, thereby sealing optical semiconductor elements.